A variety of physicochemical studies of biochemical reactions is either under way or will be initiated, with emphasis on thermochemistry and thermodynamics. Differential scanning calorimetry, using both a Yale designed and built instrument and a privalov calorimeter, is applied to: (1) protein polymerizations such as that of actin, and the assembly of microtubules; (b) phase transitions of phospholipids and their mixtures with various materials, such as the apoprotein from high density serum lipoprotein; (c) conformational transitions of proteins and nucleic acids. Isothermal calorimetry is applied to: (1) the thermodynamics of ligand binding by proteins, for example the binding of NAD ion to glyceraldehyde phosphate dehydrogenase; (b) the chelating of metal ions by cyclic peptides; the thermochemistry of active transport, for example by E. coli membrane vesicles.